Table 1 Parameters used for the AR-2 processes describing the statistics of axial and equatorial dipoles in the construction of COV-OBS.x2, compared with those used for the COV-ARCH model of Hellio and Gillet (2018), and the earlier editions COV-OBS.x1 (Gillet et al. 2015)
From: COV-OBS.x2: 180 years of geomagnetic field evolution from ground-based and satellite observations
Field model | \(\sigma _{g_1^0}\) (nT) | \(\sigma _{{\dot{g}}_1^0}\) (nT/year) | \(\omega _{g_1^0}^{-1}\) (year) | \(\chi _{g_1^0}^{-1}\) (year) | \(T_s\) (year) | \(T_f\) (year) | \(\sigma _{1}\) (nT) | \(\sigma _{{\dot{g}}_1^1}\) (nT/year) | \(\omega _{1}^{-1} (year)\) |
|---|---|---|---|---|---|---|---|---|---|
COV-ARCH | 6000 | 15 | 400 | 20 | 100,000 | 63 | 3800 | 19 | 200 |
COV-OBS.x2 | 7700 | 10 | 770 | 75 | 100,000 | 235 | 4500 | 10 | 450 |
COV-OBS.x1 | 17300 | 17 | 1014 | 1014 | 6370 | 6370 | 17300 | 17 | 1014 |